Oxidative stress induced by crude venom from the jellyfish Pelagia noctiluca in neuronal-like differentiated SH-SY5Y cells.

Marine toxins are a suitable research model and their mechanism of action is intriguing and still under debate. Either a pore formation mechanism or oxidative stress phenomena may explain the damage induced by toxins. The effect of crude venom from isolated nematocysts of the jellyfish Pelagia noctiluca on neuronal-like cells derived from human neuroblastoma SH-SY5Y has been here studied. To prove the possible oxidative stress events, cell viability, assessed by MTT quantitative colorimetric assay, intracellular reactive oxygen species (ROS) quantified by the non-fluorescent probe H2DCF-DA and changes in mitochondrial transmembrane potential (ΔΨm) measured by the incorporation of a cationic fluorescent dye rhodamine-123 were verified on venom-treated cells (0.05-0.5μg/ml doses). A dose- and time-dependent reduction of all parameters was observed after venom treatment. NAC (N-acetyl-cysteine), antioxidant applied before crude venom application, significantly counteracted the decrease in cell viability and ROS production, while ΔΨm was only partially restored. The disruption of mitochondrial membrane by P. noctiluca crude venom may thus induce oxidative stress by inhibiting mitochondrial respiration and uncoupling oxidative phosphorylation, sensitizing mitochondria in SH-SY5H cells and facilitating membrane permeability. In sum, our findings suggest that P. noctiluca crude venom directly induces ΔΨm collapse with further generation of ROS and add novel information to the understanding of such toxins, still not completely clarified.